Illumination optical system and projector including fluorophore

ABSTRACT

A projector includes an illumination optical system, an image formation element that spatially modulates light from the illumination optical system, and a projection lens that projects the spatially modulated light. The illumination optical system includes a light source that emits light of a first wavelength, a fluorophore unit including a reflection region reflecting the light of the first wavelength and a fluorophore region including a fluorophore emitting fluorescent light of a wavelength that differs from the first wavelength by irradiation of the light of the first wavelength, a first optical element reflecting a first linearly polarized light and allowing a second linearly polarized light to pass through the first optical element, and a second optical element provided on a light path between the first optical element and the fluorophore unit which changes a polarized state of irradiated light.

The present application is a Continuation Application of U.S. patentapplication Ser. No. 14/635,364, filed on Mar. 2, 2015, which is aContinuation Application of U.S. patent application Ser. No. 14/004,131,filed on Sep. 9, 2013, now U.S. Pat. No. 8,985,775, issued on Mar. 24,2015, which is based on International Application No. PCT/JP2011/056525,filed on Mar. 18, 2011, the entire contents of which are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to an illumination optical systemincluding a fluorophore unit that emits fluorescent light due toexcitation light from a light source and relates to a projectorincluding the illumination optical system.

BACKGROUND

Various illumination optical systems are currently proposed as theillumination optical system used in a projector such as an LED (LiquidCrystal Display) projector or a DLP (Digital Light Processing)projector.

Japanese Unexamined Patent Application Publication No. 2010-237443(hereinbelow referred to as Patent Document 1) and Japanese UnexaminedPatent Application Publication No. 2010-256457 (hereinbelow referred toas Patent Document 2) disclose illumination optical systems andprojectors in which a fluorophore is irradiated by an excitation lightto obtain light emission of a predetermined wavelength band from afluorophore.

The illumination optical system (light source device) disclosed in eachof these patent documents is equipped with a light source thatirradiates laser light of the blue wavelength band and a light-emittingwheel on which is provided a light-emitting substance that emits lightwith light irradiated from the light source as excitation light. Thelight-emitting wheel is provided with: a red region in which alight-emitting substance is provided that emits light of the redwavelength band when excited by light from the light source, a greenregion in which a light-emitting substance is provided that emits lightof the green wavelength band, and a blue region that transmits light ofthe blue wavelength band. The light-emitting substances of thelight-emitting wheel are formed on a reflection layer.

The light-emitting wheel is configured so as to be rotatable. Due to therotation of the fluorophore wheel, blue light that is emitted from thelight source successively irradiates the red region, the green region,and the transmission region of the light-emitting wheel. The red lightand green light generated from the fluorophores are reflected by thereflection layer.

Red light and green light that are reflected by the reflection layer andblue light that is transmitted by the transmission region are combinedby a dichroic mirror or relay optical system. The combined light isirradiated upon a digital mirror device (DMD). Light of each color thatis emitted in time divisions by the light-emitting wheel is- spatiallymodulated according to input images by the DMD and projected by way of aprojection lens onto a screen.

LITERATURE OF THE PRIOR ART Patent Documents

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2010-237443

Patent Document 2: Japanese Unexamined Patent Application PublicationNo. 2010-256457

SUMMARY Technical Problem

In the case of the illumination optical systems described in PatentDocument 1 and Patent Document 2, the light path of blue light differsfrom the light path of red light and green light. This difference occursbecause the blue light is transmitted through the fluorophore wheelwhile the red light and green light are reflected by the fluorophorewheel. As a result, the optical system through which the blue lightpasses differs from the optical system through which the red light andgreen light pass.

In order for the blue light and red and green light that pass overdifferent light paths to be emitted from the illumination optical systemin the same direction, an optical system is absolutely necessary thatcombines the light paths of the light of each color. The problemtherefore arises in which the size of the illumination optical systemincreases or in which the number of optical parts that make up theillumination optical system increases.

A compact illumination optical system having few optical parts istherefore desired in the illumination optical system that includes afluorophore that produces fluorescent light by the irradiation ofexcitation light.

Solution to Problem

The illumination optical system of one aspect of the present inventioncomprises: a light source emitting light of a first wavelength; afluorophore unit; an optical element; and a quarter-wave plate that isprovided on the light path between the optical element and thefluorophore unit. The fluorophore unit includes: a fluorophore region inwhich a fluorophore that, by the irradiation of light of the firstwavelength, emits fluorescent light of a wavelength that differs fromthe first wavelength, and a reflection region that reflects light of thefirst wavelength. The fluorophore unit can move such that light from thelight source is successively irradiated on the fluorophore region andthe reflection region. The optical element separates light of the firstwavelength into a first linearly polarized light component and a secondlinearly polarized light component that is orthogonal to the firstlinearly polarized light component and guides the first linearlypolarized light component that is emitted from the light source to thefluorophore unit. Light that is reflected by the reflection region andlight emitted by the fluorophore region are again irradiated into theoptical element. The optical element emits light of the first wavelengththat was reflected by the reflection region and fluorescent light thatwas emitted by the fluorophore region in the same direction.

The projector of the present invention includes the above-describedillumination optical system.

According to the above-described configuration, light of the firstwavelength that is reflected in the fluorophore unit and fluorescentlight that is emitted from a fluorophore both pass by way of the samelight path and optical system. Accordingly, the number of constituentparts of the illumination optical system is decreased and the size ofthe illumination optical system is reduced.

The above and other objects, characteristics, and merits of the presentinvention will become clear from the following explanation that refersto the accompanying drawings that present examples of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the configuration of a projector thatincludes the illumination optical system according to the firstexemplary embodiment of the present invention.

FIG. 2 is a plan view showing one surface upon which light from a lightsource is irradiated in the fluorophore unit shown in FIG. 1.

FIG. 3 is a graph showing the transmission property of light of theoptical element belonging to the illumination optical system accordingto the first exemplary embodiment.

FIG. 4 is a schematic view showing the configuration of a projector thatincludes the illumination optical system according to the secondexemplary embodiment of the present invention.

FIG. 5 is a graph showing the transmission property of light of theoptical element belonging to the illumination optical system accordingto the second exemplary embodiment.

DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the present invention are next described withreference to the accompanying drawings.

FIG. 1 shows the configuration of a projector that includes theillumination optical system according to the first exemplary embodimentof the present invention. The projector includes: illumination opticalsystem 10, image formation element 22 that spatially modulates lightfrom illumination optical system 10, and projection lens 24 thatprojects light that was spatially modulated by image formation element22.

Illumination optical system 10 includes: light source 11 that emitslight of a first wavelength, optical element 13, quarter-wave plate 14,and fluorophore unit 16. Fluorophore unit 16 includes fluorophore thatemits fluorescent light by the irradiation of light of the firstwavelength. Light source 11 functions as a light source that not onlyemits light of the first wavelength that is emitted from illuminationoptical system 10 but also irradiates excitation light onto thefluorophore.

Quarter-wave plate 14 is provided between optical element 13 andfluorophore unit 16. As needed, illumination optical system 10 may alsoinclude, for example, collimators 12 and 15.

FIG. 2 is a plan view of fluorophore unit 16 as seen from the directionof the incidence of excitation light. Fluorophore unit 16 includesreflection region 16 a and fluorophore regions 16 b and 16 c. Reflectionregion 16 a is a region having a reflection film or mirror that reflectsat least light of the first wavelength.

In the example shown in FIG. 2, the fluorophore regions include: firstfluorophore region 16 b in which a fluorophore is provided that, by theirradiation of light of the first wavelength, emits light of a secondwavelength that is longer than the first wavelength; and secondfluorophore region 16 c in which a fluorophore is provided that, by theirradiation of light of the first wavelength, emits light of a thirdwavelength that is even longer than the second wavelength. Influorophore regions 16 b and 16 c, the fluorophores are provided on areflection surface that reflects light.

In order to realize a projector capable of displaying full-color imagesin the present exemplary embodiment, the light of the first wavelengthis blue light, the light of the second wavelength is green light, andthe light of the third wavelength is red light.

Fluorophore unit 16 is able to move such that the irradiation spot S oflight from light source 11 irradiates reflection region 16 a andfluorophore regions 16 b and 16 c in time divisions. More specifically,fluorophore unit 16 is configured to freely rotate around rotation axis28 that is orthogonal to the surface on which the reflection region andthe fluorophore regions are provided. Fluorophore unit 16 is caused torotate by motor 17. The light from light source 11 successivelyirradiates reflection region 16 a and fluorophore regions 16 b and 16 cdue to the rotation of fluorophore unit 16.

In the example shown in FIG. 2, reflection region 16 a and fluorophoreregions 16 b and 16 c are generally fan-shaped regions having a centralangle of a predetermined size. The proportions of each of the centralangles of reflection region 16 a and fluorophore regions 16 b and 16 cmatch the proportions of time when light is irradiated from light source11 to each of the corresponding regions. Accordingly, the sizes ofreflection region 16 a and fluorophore regions 16 b and 16 c, which arethe central angles in this case, are set according to, for example, theuse of the illumination optical system.

In the present exemplary embodiment, the sizes of reflection region 16 aand each of fluorophore regions 16 b and 16 c can be determined based onthe intensity and chromaticity coordinates of light that is projected ona screen by way of projection lens 24 of the projector. In particular,the proportions of the central angles of reflection region 16 a andfluorophore regions 16 b and 16 c are preferably determined by givingconsideration to the intensity and chromaticity of white light that isformed by combining the light of each color.

Optical element 13 guides the first linearly polarized light componentof light that is emitted from light source 11 to fluorophore unit 16.The light that is reflected and the light that is emitted by thefluorophores in fluorophore unit 16 are again irradiated into opticalelement 13. Optical element 13 emits the light of the first wavelengththat is reflected in fluorophore unit 16 and light of the secondwavelength that is emitted in fluorophore unit 16 in the same direction.

A dichroic mirror having a predetermined spectral transmittancecharacteristic can be used as this optical element 13.

In the above-described exemplary embodiment, the first linearlypolarized light component is an S-polarized light component that isorthogonal to the incidence plane on dichroic mirror 13. The secondlinearly polarized light component is a P-polarized light component thatis parallel to the incidence plane on dichroic mirror 13.

FIG. 3 shows the spectral transmittance characteristic of dichroicmirror 13 and the spectrum of light that is transmitted from lightsource 11. Dichroic mirror 13 has a characteristic such that theS-polarized light component of blue light of a wavelength on the orderof 450 nm is reflected and the P-polarized light component of blue lightis transmitted, whereby dichroic mirror 13 is able to separate lightthat is emitted from light source 11 into an S-polarized light componentand a P-polarized light component that is orthogonal to the S-polarizedlight component. Dichroic mirror 13 guides substantially only light ofthe S-polarized light component to fluorophore unit 16.

More specifically, relating to the S-polarized light component, dichroicmirror 13 reflects light of wavelengths no greater than the wavelengthof blue light and transmits light of wavelengths sufficiently longerthan the wavelength of blue light. Further, relating to the P-polarizedlight component, dichroic mirror 13 reflects light of sufficientlyshorter wavelengths than the wavelength of blue light and transmitslight of wavelengths equal to or greater than the wavelength of bluelight. As a result, dichroic mirror 13 reflects the S-polarized lightcomponent and transmits the P-polarized light component in thewavelength band of blue light. The spectrum of light that is emittedfrom light source 11 belongs to the wavelength band of this blue light.

Dichroic mirror 13 can be constituted by a multilayer film ofdielectrics each having different refractive indices. The dichroicmirror having the spectral reflectance characteristic shown in FIG. 3 iseasily fabricated by appropriately adjusting the refractive indices ofeach of the dielectric films, the film thicknesses, and the number oflaminated layers of dielectrics to determine the desired cutoffwavelength.

In the present exemplary embodiment, light source 11 is preferably acomponent that emits light having substantially only the S-polarizedlight component. Most of the light from light source 11 is guidedthrough dichroic mirror 13 to fluorophore unit 16, whereby theefficiency of the utilization of light of illumination optical system 10is improved. A blue laser that emits light of a blue wavelength, forexample, a wavelength in the vicinity of 450 nm, can be used as thislight source 11.

When the light source of the blue excitation light that excites thefluorophores is a laser, irradiation spot S of the excitation light canbe made an extremely small surface area. As a result, the irradiationsurface area upon fluorophore unit 16 can be reduced, the etendue can bedecreased, and a high-efficiency illumination optical system can berealized.

The light paths of the light in the illumination optical system of theconfiguration shown in FIG. 1 are next described. Light generated fromlight source 11 is converted to parallel light by collimator 12. TheS-polarized light component of this parallel light is reflected bydichroic minor 13 and guided in the direction of fluorophore unit 16.

In FIG. 1, collimator 12 is made up of one lens, but collimator 12 maybe a lens system made up of a plurality of lenses.

S-polarized light that is reflected by dichroic mirror 13 passes by wayof quarter-wave plate 14 and collimator 15 and is then incident tofluorophore unit 16. The S-polarized light is converted to circularlypolarized light by quarter-wave plate 14, and this circularly polarizedlight is condensed on reflection region 16 a or fluorophore regions 16 band 16 c of fluorophore unit 16.

In FIG. 1, collimator 15 is a lens system made up of two lenses, butcollimator 15 may be one lens or may be a lens system made up of threeor more lenses.

When light of the first wavelength is irradiated upon first fluorophoreregion 16 b of fluorophore unit 16, green light is emitted from thefluorophore. This green light advances in the opposite direction on thelight path of blue light that is incident to fluorophore unit 16 and isconverted to parallel light by collimator 15.

Green light that has been converted to parallel light is transmittedthrough quarter-wave plate 14 and again irradiated into dichroic mirror13. The Lambert diffused light that is emitted from the fluorophore isunpolarized light, i.e., randomly polarized light, and despite passagethrough quarter-wave plate 14, the polarized state of the light does notchange.

The green light passes through dichroic mirror 13 as shown in FIG. 3.Accordingly, the green light is emitted in a direction that differs fromthe position of arrangement of light source 11.

When light of the first wavelength is incident to second fluorophoreregion 16 c of fluorophore unit 16, red light is emitted from thefluorophore. This red light passes by way of the same light path as thegreen light that is emitted from the first fluorophore region 16 b andis again incident to dichroic minor 13. The red light passes throughdichroic mirror 13 as shown in FIG. 3. Accordingly, the red light isemitted in the same direction as the green light.

When blue light that is guided from light source 11 to fluorophore unit16 is incident to reflection region 16 a of fluorophore unit 16, theblue light is reflected. The reflected blue light passes along a lightpath similar to that of the red light and green light that were emittedby fluorophore regions 16 b and 16 c and passes through collimator lens15 and quarter-wave plate 14.

The blue light that is reflected by reflection region 16 a is convertedfrom circularly polarized light to P-polarized light by quarter-waveplate 14 and then incident to dichroic mirror 13. The P-polarized bluelight passes through the dichroic minor as shown in FIG. 3.

Accordingly, the blue light that is reflected by reflection region 16 ais emitted from illumination optical system 10 by way of a light pathsimilar to that of the green light and red light.

As described hereinabove, dichroic mirror 13 functions as a polarizationbeam splitter with respect to light of the blue wavelength band, wherebyblue light that is reflected by reflection region 16 a of thefluorophore unit is emitted in a direction that differs from lightsource 11, i.e., in the same direction as green light and red light.

According to the above-described configuration, blue light that isreflected at reflection region 16 a of fluorophore unit 16 and red lightand green light that are emitted from fluorophore regions 16 b and 16 call pass through the same optical system. Accordingly, a separateoptical system need not be used for each wavelength of light, wherebythe number of constituent parts of illumination optical system 10 can bedecreased and the size of the illumination optical system can bereduced.

Light that has passed by way of dichroic mirror 13 of illuminationoptical system 10 is irradiated upon image formation element 22 by wayof integrator 18, field lens 19, minor 20, condenser lens 21, and TIRprism 23. Integrator 18, field lens 19, and condenser lens 21 areprovided to irradiate light both uniformly and as a rectangle on imageformation element 22. Integrator 18, field lens 19, mirror 20, andcondenser lens 21 may be constituent elements of the illuminationoptical system.

Light that is incident to TIR prism 23 is reflected at air gap surface23 a in the prism to undergo a change of direction of advance and isthen emitted toward image formation element 22. The angle of the lightbeam that is emitted to image formation element 22 is appropriatelyadjusted by mirror 20 and TIR prism 23.

In the projector of the present exemplary embodiment, reflective-typeimage formation element 22 is used. In this case, a DMD is used asreflective image formation element 22.

Instead of a DMD, a liquid crystal panel (LCD), which is atransmissive-type image formation element, can also be used as imageformation element 22.

A DMD has as many micro-mirror elements as the number of pictureelements. Each micro mirror element is configured to allow movement by apredetermined angle around an axis of rotation. In this example, themirror elements rotate ±12 degrees.

Light that is incident to mirror elements that are tilted +12 degrees isreflected in the direction in which projection lens 24 is arranged.Light that is incident to projection lens 24 is projected to outside theprojector. Light that is incident to a mirror element tilted −12 degreesis reflected in a direction in which projection lens 24 is not arranged.In this way, each mirror element selects whether light corresponding toa picture element is projected to outside the projector. By the DMDcarrying out control for the light of each color, the projector is ableto display color images on a screen.

Projection lens 24 can be composed of an optical system for enlargedprojection. Light of each color from illumination optical system 10 isirradiated to image formation element 22 in time divisions. Light ofeach color that is incident to image formation element 22 is subjectedto spatial modulation according to image information that is received asinput to convert to image light. The spatially modulated image light isprojected onto a screen by projection lens 24.

FIG. 4 is a schematic view showing the configuration of a projector thatincludes illumination optical system 40 according to the secondexemplary embodiment of the present invention. The projector includes:illumination optical system 40, image formation element 22 thatspatially modulates the light from illumination optical system 40, andprojection lens 24 that projects light that has been spatially modulatedby image formation element 22.

Illumination optical system 40 includes: light source 41 that emitslight of the first wavelength, optical element 43, quarter-wave plate14, and fluorophore unit 16. Quarter-wave plate 14 is provided betweenoptical element 43 and fluorophore unit 16. Illumination optical system40 may also have collimators 12 and 15 according to necessity.

Light source 41 in the second exemplary embodiment is preferably a bluelaser that emits P-polarized excitation light. Light from light source41 is converted to parallel light by collimator 12 and irradiated intodichroic mirror 43 that serves as the optical element.

FIG. 5 shows the spectral transmittance characteristic of dichroic minor43 and the spectrum of light that is generated from light source 41.Dichroic minor 43 has a characteristic by which the P-polarized lightcomponent of blue light is transmitted and the S-polarized lightcomponent of blue light is reflected. Dichroic minor 43 is thus able toseparate light that is emitted from light source 41 into a P-polarizedlight component as the first linearly polarized light component and anS-polarized light component as the second linearly polarized lightcomponent. In the present exemplary embodiment, dichroic minor 43 guidessubstantially only the P-polarized light component as the first linearlypolarized light component to fluorophore unit 16.

As a more specific example, with relation to the P-polarized lightcomponent, dichroic minor 43 transmits light of wavelengths equal to orless than the wavelength of blue light and reflects light of wavelengthssufficiently longer than the wavelength of blue light. Further, relatingto the S-polarized light component, the dichroic mirror transmits lightof wavelengths sufficiently shorter than the wavelength of blue lightand reflects light of wavelengths equal to or greater than thewavelength of blue light. Dichroic minor 43 thus reflects theS-polarized light component and transmits the P-polarized lightcomponent in the wavelength band of blue light. The spectrum of lightemitted from light source 41 belongs to the wavelength band of this bluelight.

Dichroic mirror 43 can be configured from a multilayer film ofdielectrics each having different refractive indices. Dichroic mirror 43having the spectral reflectance characteristic shown in FIG. 5 is easilyfabricated by appropriately adjusting, for example, the refractiveindices and the film thicknesses of dielectric film or the number oflaminations of dielectrics to determine a predetermined cutoffwavelength.

The P-polarized light component of blue light that is transmitted bydichroic mirror 43 passes through quarter-wave plate 14 and collimatorlens 15 and is irradiated into fluorophore unit 16. The P-polarizedlight is converted to circularly polarized light by quarter-wave plate14, and this circularly polarized light is condensed in fluorophore unit16.

The configuration of fluorophore unit 16 is similar to that of the firstexemplary embodiment. When blue light from light source 41 is irradiatedinto fluorophore regions 16 b and 16 c of fluorophore unit 16, light ofa wavelength longer than that of the wavelength of blue light is emittedfrom the fluorophores. In the present exemplary embodiment, thefluorophores applied to fluorophore regions 16 b and 16 c emit greenlight or red light.

The light that is emitted from the fluorophores is changed to parallellight by collimator lens 15, passes through quarter-wave plate 14, andis again irradiated into dichroic mirror 43. As shown in FIG. 5,dichroic mirror 43 reflects red light and green light. The red light andgreen light that are emitted from fluorophore regions 16 b and 16 c aretherefore reflected at dichroic mirror 42 and emitted in the samedirection from illumination optical system 40.

When blue light from light source 41 is irradiated into reflectionregion 16 a of fluorophore unit 16, the blue light is reflected,advances along the same light path as the red light and green light, andpasses through collimator lens 15 and quarter-wave plate 14.

This blue light is converted from circularly polarized light toS-polarized light by quarter-wave plate 14 and irradiated into dichroicminor 43. As shown in FIG. 5, dichroic minor 43 reflects S-polarizedexcitation light, whereby the blue light that is reflected by reflectionregion 16 a passes along the same light path as the red light and greenlight and is emitted from illumination optical system 40.

According to the above-described configuration, different opticalsystems need not be used for each wavelength of light, whereby thenumber of constituent parts of illumination optical system 40 isdecreased and the size of the illumination optical system is alsoreduced.

The light reflected by dichroic mirror 43 of illumination optical system40 is irradiated into image formation element 22 by way of integrator18, mirror 20, field lens 19, condenser lens 21, and TIR prism 23. Thelight that is converted to image light by image formation element 22 isenlarged and projected onto a screen by projection lens 24. As in thefirst exemplary embodiment, a DMD can be used as image formation element22.

Integrator 18, field lens 19, and condenser lens 21 are provided forilluminating light on image formation element 22 both uniformly and as arectangle. Integrator 18, mirror 20, field lens 19, and condenser lens21 may be constituent elements of illumination optical system 40.

Fluorophore units 10 and 40 in the above-described first and secondexemplary embodiments have two types of fluorophore regions 16 b and 16c. The fluorophore unit is not limited to this form and may have onetype or three or more types of fluorophore regions. The wavelength oflight that is emitted from each fluorophore region is selected asappropriate according to the use of the illumination optical system.

In an illumination optical system that includes a fluorophore unithaving a reflection region and only one type of fluorophore region,light generated by the light source and fluorescent light that isgenerated by the fluorophore can be emitted in the same direction alongthe same light path. Accordingly, in an illumination optical system thatemits two types of light, the light generated by the light source andthe fluorescent light from the fluorophore, the number of constituentparts can be decreased and the size can be reduced. When a projectorthat displays full color is configured using this type of illuminationoptical system, another separate light source should be used.

Although a detailed explanation has been presented regarding preferableexemplary embodiments of the present invention, the present invention isnot limited to the above-described exemplary embodiments, and it shouldbe understood that the present invention is open to variousmodifications and amendments that do not depart from the gist of thepresent invention.

REFERENCE SIGNS LIST

-   10, 40 projector-   11, 41 light source-   12 collimator-   13, 43 dichroic mirror (optical element)-   14 quarter-wave plate-   15 collimator-   16 fluorophore unit-   16 a reflection region-   16 b fluorescent region-   16 c fluorescent region-   17 motor-   18 integrator-   19 field lens-   20 mirror-   21 condenser lens-   22 image formation element-   23 TIR prism-   23 a air gap surface-   24 projection lens

What is claimed is:
 1. A projector, comprising: an illumination opticalsystem; an image formation element that spatially modulates light fromthe illumination optical system; and a projection lens that projects thespatially modulated light, wherein the illumination optical systemcomprises: a light source that emits light of a first wavelength; afluorophore unit including a reflection region reflecting the light ofsaid first wavelength and a fluorophore region including a fluorophoreemitting fluorescent light of a wavelength that differs from said firstwavelength by irradiation of the light of said first wavelength; a firstoptical element reflecting a first linearly polarized light and allowinga second linearly polarized light to pass through the first opticalelement; and a second optical element provided on a light path betweensaid first optical element and said fluorophore unit which changes apolarized state of irradiated light.
 2. The projector according to claim1, wherein said first optical element emits the light of said firstwavelength reflected by said reflection region and said fluorescentlight emitted by said fluorophore region in a same direction.
 3. Theprojector according to claim 1, wherein said fluorophore unit isconfigured to move such that the light from said light source issuccessively irradiated on said fluorophore region and said reflectionregion.
 4. The projector according to claim 1, wherein said light of thefirst wavelength reflected by said first optical element includes afirst linearly polarized light component, the first optical elementguiding said first linearly polarized light component emitted from saidlight source to said fluorophore unit, and the first optical elementbeing again irradiated by light reflected on said reflection region andby light emitted from said fluorophore region.
 5. The projectoraccording to claim 1, wherein said light of the first wavelengthreflected by said first optical element includes a first linearlypolarized light component, and said first linearly polarized lightcomponent of light from said light source passes through said secondoptical element and is converted to a polarized light, said polarizedlight being irradiated into said fluorophore unit.
 6. The projectoraccording to claim 1, wherein said first optical element separates thelight of said first wavelength into a first linearly polarized lightcomponent and a second linearly polarized light component, and saidfirst optical element reflects said first linearly polarized lightcomponent of the light of said first wavelength and transmits saidfluorescent light and said second linearly polarized light component oflight of said first wavelength.
 7. The projector according to claim 1,wherein said first linearly polarized light component comprises anS-polarized light component that is orthogonal to an incidence plane onsaid optical element, and said second linearly polarized light componentcomprises a P-polarized light component that is parallel to saidincidence plane.